For a period of four years, researchers followed 169 couples on their first marriage. They measured the couples’ weight twice a year, and asked questions about their marital life and overall satisfaction.

The results? People in happy marriages gained a significant amount of weight.

Meanwhile, those who remained slim reported rocky marriages that eventually ended in divorce.

The researchers theorize that the phenomena has something to do with attracting mates. Happier couples no longer feel the need to attract a new mate; therefore, there’s less stress on appearance. Meanwhile, those in rocky relationships maintain their slim figure to continue attracting mates.

Although these couples don’t have to worry about their partner only loving them for their looks, that leaves the question on whether stable relationships have a negative impact on health.

Psychologist Andrea L. Meltzer, who led the research, said that couples should pay attention when it comes to their weight gain, because it can lead to health consequences such as diabetes and cardiovascular disease.

“By focusing more on weight in terms of health implications as opposed to appearance implications, satisfied couples may be able to avoid potentially unhealthy weight gain over time in their marriages,” she said.

There’s nothing wrong with not paying attention to your appearance, because you’re confident that your spouse would continue to love you despite it.